package NIO;
/*
 * @Author  Wrial
 * @Date Created in 11:10 2020/4/12
 * @Description
 */


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Set;

public class EchoClient {
    private SocketChannel socketChannel = null;
    private ByteBuffer sendBuffer = ByteBuffer.allocate(1024);
    private ByteBuffer receiveBuffer = ByteBuffer.allocate(1024);
    private Charset charset = Charset.forName("UTF-8");
    private Selector selector;

    public EchoClient() throws IOException {
        socketChannel = SocketChannel.open();
//        InetAddress ia = InetAddress.getLocalHost();
        InetSocketAddress isa = new InetSocketAddress("localhost",8090);
        socketChannel.connect(isa);
        socketChannel.configureBlocking(false);
        System.out.println("与服务器的连接建立成功");
        selector = Selector.open();
    }

    public static void main(String[] args) throws IOException {
        final EchoClient client = new EchoClient();
        Thread receiver = new Thread(){
            public void run(){
                client.receiveFromUser();
            }
        };
        receiver.start();
        client.talk();
    }

    public void receiveFromUser(){
        try{
            BufferedReader localReader = new BufferedReader(new InputStreamReader(System.in));
            String msg = null;
            while((msg = localReader.readLine())!=null){
                synchronized (sendBuffer) {
                    sendBuffer.put(encode(msg+"\r\n"));
                }
                if(msg.equals("bye"))
                    break;
            }
        }catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void talk()throws IOException{
        try{
            socketChannel.register(selector, SelectionKey.OP_READ|SelectionKey.OP_WRITE);
            while(selector.select()>0){
                Set readyKeys = selector.selectedKeys();
                Iterator it = readyKeys.iterator();
                while(it.hasNext()){
                    SelectionKey key = null;
                    try{
                        key = (SelectionKey)it.next();
                        it.remove();
                        if(key.isReadable()){
                            receive(key);
                        }
                        if(key.isWritable()){
                            send(key);
                        }
                    }catch (IOException e) {
                        e.printStackTrace();
                        try{
                            if(key!=null){
                                key.cancel();
                                key.channel().close();
                            }
                        }catch (Exception ex) {
                            ex.printStackTrace();
                        }
                    }
                }
            }
        }catch (IOException e) {
            e.printStackTrace();
        }finally{
            try{
                socketChannel.close();
            }catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    public void send(SelectionKey key)throws IOException{
        SocketChannel socketChannel = (SocketChannel) key.channel();
        synchronized (sendBuffer) {
            sendBuffer.flip();
            socketChannel.write(sendBuffer);
            sendBuffer.compact();
        }
    }
    public void receive(SelectionKey key)throws IOException{
        //接收EchoServer发送的数据，把它放到receiveBuffer中
        //如果receiverBuffer中有一行数据，就打印这行数据，然后把它从receiverBuffer中删除
        SocketChannel socketChannel = (SocketChannel) key.channel();
        socketChannel.read(receiveBuffer);
        receiveBuffer.flip();
        String receiveData = decode(receiveBuffer);
        if(receiveData.indexOf("\n") == -1){
            return;
        }
        String outputData = receiveData.substring(0,receiveData.indexOf("\n")+1);
        System.out.println(outputData);
        if(outputData.equals("echo:bye\r\n")){
            key.cancel();
            socketChannel.close();
            System.out.println("关闭与服务器的连接");
            selector.close();
            System.exit(0);
        }
        ByteBuffer temp = encode(outputData);
        receiveBuffer.position(temp.limit());
        receiveBuffer.compact();
    }
    public String decode(ByteBuffer buffer){
        CharBuffer charBuffer = charset.decode(buffer);
        return charBuffer.toString();
    }
    public ByteBuffer encode(String str){
        return charset.encode(str);
    }
}